+(defun make-byte-tn (tn)
+ (aver (sc-is tn any-reg descriptor-reg unsigned-reg signed-reg))
+ (make-random-tn :kind :normal
+ :sc (sc-or-lose 'byte-reg)
+ :offset (tn-offset tn)))
+
+(defun make-dword-tn (tn)
+ (aver (sc-is tn any-reg descriptor-reg character-reg
+ unsigned-reg signed-reg))
+ (make-random-tn :kind :normal
+ :sc (sc-or-lose 'dword-reg)
+ :offset (tn-offset tn)))
+
+(defun zeroize (tn)
+ (let ((offset (tn-offset tn)))
+ ;; Using the 32-bit instruction accomplishes the same thing and is
+ ;; one byte shorter.
+ (if (<= offset edi-offset)
+ (let ((tn (make-random-tn :kind :normal
+ :sc (sc-or-lose 'dword-reg)
+ :offset offset)))
+ (inst xor tn tn))
+ (inst xor tn tn))))
+